Drive sleeve and sealing mechanism for non-rising stem gate valve

ABSTRACT

A non-rising stem gate valve is provided that includes a drive sleeve disposed between the gate and the stem. The drive sleeve is coupled to the stem and isolates the moveable connection between the sleeve and the stem from fluid in the valve. The drive sleeve is also coupled to the gate such that movement of the drive sleeve along the stem moves the gate between the open and closed positions of the valve. Systems and methods incorporating the non-rising stem gate valve are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/133,831, entitled “Drive Sleeve and Sealing Mechanism for Non-RisingStem Gate Valve,” filed Jun. 9, 2011, which is herein incorporated byreference in its entirety, which is a National Stage of PCT PatentApplication No. PCT/US2010/020823, entitled “Drive Sleeve and SealingMechanism for Non-Rising Stem Gate Valve,” filed Jan. 12, 2010, which isherein incorporated by reference in its entirety, and which claimspriority to and benefit of U.S. Provisional Patent Application No.61/149,978, entitled “Drive Sleeve and Sealing Mechanism for Non-RisingStem Gate Valve”, filed on Feb. 4, 2009, which is herein incorporated byreference in its entirety.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

As will be appreciated, oil and natural gas have a profound effect onmodern economies and societies. Indeed, devices and systems that dependon oil and natural gas are ubiquitous. For instance, oil and natural gasare used for fuel in a wide variety of vehicles, such as cars,airplanes, boats, and the like. Further, oil and natural gas arefrequently used to heat homes during winter, to generate electricity,and to manufacture an astonishing array of everyday products.

In order to meet the demand for such natural resources, companies ofteninvest significant amounts of time and money in searching for andextracting oil, natural gas, and other subterranean resources from theearth. Particularly, once a desired resource is discovered below thesurface of the earth, drilling and production systems are often employedto access and extract the resource. These systems may be located onshoreor offshore depending on the location of a desired resource. Once thenatural resource is extracted, it is generally transported to processinglocations, such as refineries. The transportation of these resources isaccomplished through a system of pipelines, which are controlled throughvarious types of valves located at different points throughout thesystem.

Such extraction systems may include pipelines or other transportationstructures to transport the resource from a source, e.g., a well, to adestination such as further transportation systems or storagefacilities. Such pipelines or other transportation structures mayinclude pressure control, regulation, safety devices, which may includevalves, actuators, sensors, and electronic circuitry. Such devices maybe configured to relieve pressure or shut off flow of the resource if ahigh pressure condition is detected.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present invention willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a front view of a non-rising stem gate valve in accordancewith an embodiment of the present invention;

FIG. 2 is a cross-section of the non-rising stem gate valve of FIG. 1 ina closed position in accordance with an embodiment of the presentinvention;

FIG. 3 is a cross-section of the non-rising stem gate valve of FIG. 1 inan open position in accordance with an embodiment of the presentinvention;

FIG. 4 is a close-up of a drive sleeve of the non-rising stem gate valveof FIG. 1 in accordance with an embodiment of the present invention; and

FIG. 5 is a mineral extraction system using a non-rising stem gate valvein accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

One type of valve referred in a mineral extraction system may bereferred to as a gate valve. A gate valve includes a gate that may bemoved between an open position to allow fluid flow through the valve,and a closed position to block fluid flowing through the valve. The gatevalve may include a stem to enable movement of the gate, either throughmovement of the stem (rising stem gate valve) or movement of the gatealong the stem (non-rising stem gate valve). The non-rising stem gatevalve may offer some advantages over a rising stem gate valve, such asreduced dimensional profile and reduced input torque. However, in somesystems using a non-rising stem gate valve, the non-rising stem may beexposed to fluid flowing through the valve. Such fluid may be corrosiveand/or abrasive, and may include abrasive materials that result inincreased wear of the gate valve. Such abrasion may eventually mayinterfere with operation of the gate valve and damage the non-risingstem, the gate, or the connection between the non-rising stem and thegate.

Embodiments of the present invention include a non-rising stem gatevalve having a drive sleeve to isolate a moveable connection between thevalve stem and the drive sleeve from fluid in the valve. The drivesleeve is coupled to both the valve gate and the valve stem, enablingmovement of the drive sleeve along the stem to move the gate and openand close the valve. The connection between the valve gate and the drivesleeve may also be isolated from any fluid in the valve. The drivesleeve may include a sealing component to seal the upper end of thedrive sleeve from pressure in the valve body. Additionally, the stem maybe coated in a lubricant (e.g., a dry film lubricant) and anotherlubricant (e.g., grease) may be disposed in the cavity defined by thedrive sleeve and the stem. The stem may include a chamber to allow thelubricant to flow into and out of the cavity during movement of thedrive sleeve.

FIG. 1 is a front view of a non-rising stem gate valve 10 having a drivesleeve in accordance with an embodiment of the present invention. Thenon-rising stem gate valve 10 may include a valve body 12 coupled to avalve bonnet 14 via one or more bolts 16. The valve 10 may include anon-rising stem 18 (also referred to as a shaft) extending out of theupper portion of the bonnet 14. The stem 18 may be coupled to ahandwheel 20 extending from the bonnet 14. As seen further below, thehandwheel 20 enables rotation of the stem 18 to actuate the valve 10between open and closed positions. The handwheel 20 may be operated by ahuman operator or may be automatically operated by a hydraulic orelectric drive system. In other embodiments, the actuation mechanism ofthe valve 10 may include a hydraulic and/or electric actuator instead ofthe handwheel 20.

The valve 10 includes an inlet passage 22 and an outlet passage 24 toprovide connection to piping or other components. For example, the valve10 may be placed between an upstream pipe 26 transporting a fluid from asource and a downstream pipe 28 transporting the fluid to downstreamequipment. In such an embodiment, the valve 10 may be used in an on/offmanner to allow or block flow from the upstream pipe 26 through thevalve 10 and into the downstream pipe 28. In other embodiments, thevalve 10 may be used to regulate (e.g., choke) flow from the upstreampipe into the downstream pipe 28.

In some embodiments, the fluid flowing through the valve (also referredto as “valve lading”) may be abrasive, e.g., the valve lading mayinclude particulates or other materials that could abrade internalcomponents of the valve 10. For example, such abrasive valve lading mayinclude drilling muds, sand, silica, or any combination thereof. Othervalve ladings may be corrosive or have other properties that coulddamage internal components of the valve 10.

FIG. 2 is a cross-section of the valve 10 taken along line 1-1 of FIG. 1that depicts the valve 10 in a closed position in accordance with anembodiment of the present invention. As described further below, thevalve 10 includes a drive sleeve 30 to protect internal components fromthe valve lading. The valve 10 includes the stem 18, the drive sleeve30, and a slab gate 32. The drive sleeve 30 may be generally tubular andconcentric with the stem 18. It should be appreciated that the term“slab gate” refers to the design of the gate 32, and other embodimentsmay include different types of gates that operate according to themechanism described herein.

The gate 32 includes a port 34 that allows fluid flow through the valvebody 12 when the gate 32 is in the open position. The valve body 12 alsoincludes an inlet seat 36 and an outlet seat 38. Thus, by moving thegate 32 such that the port 34 is aligned with the inlet seat 36 andoutlet seat 38, the valve 10 may be opened. Similarly, by moving thegate 32 such that the upper portion of the gate 32 is disposed betweenthe inlet seat 36 and outlet seat 38, the valve 10 may be closed. Itshould be appreciated that the valve 10 may be bi-directional, and theterms “inlet” and “outlet” are used for ease of reference and do notdescribe any specific directional limitation of the valve 10. Forexample, the seats 36 and 28 may be either inlet or outlet seatsrespectively, and the flanges 22 and 24 may also be either inlet oroutlet flanges respectively.

The valve body 12 includes the inlet passage 22 and outlet passage 24,and a chamber or body cavity 40 in fluid communication with the inletpassage 22 and outlet passage 24. As described, abrasive valve lading inthe passages 22 and 24 and the chamber 40 may abrade internal componentsof the valve 10. For example, in a non-rising stem gate valve withoutaspects of the disclosed embodiments, gate travel may be providedthrough rotation of the stem 18 at a threaded connection between thegate and stem. This threaded connection may be exposed to the valvelading, and abrasive damage to the threaded connection may occur. Inembodiments of the present invention, the drive sleeve 30 is interposedbetween the slab gate 32 and the stem 18, isolating the gate connectionand the thread connection from the valve lading.

Turning now in more detail to the drive sleeve 30 and gate 32, the drivesleeve 30 is coupled to the stem 18 at a drive sleeve/stem interface 41and the gate 32 is coupled to the drive sleeve 30 at a gate/drive sleeveinterface 43. The drive sleeve 30 includes internal threads 42 to coupleto the stem 18. The stem 18 may include threads 44 to allow travel(e.g., translation) of the drive sleeve 30 up and down the stem 18 asthe stem 18 rotates. In some embodiments, the threads 42 and 44 may bepower threads, such as acme threads, square threads, or any suitablethreads. In some embodiments, the drive sleeve 30 may consistessentially of stainless steel or any suitable material.

The drive sleeve 30 may include external threads 46 to couple to thegate 32. The gate 32 may include internal threads 48 to couple to theexternal threads 46 of the drive sleeve 30. The drive sleeve/gateinterface 43 may also include a locking fastener 50, such as a pin,screw, or other suitable fastener. The locking fastener 50 locks thedrive sleeve 30 to the gate 32. In other embodiments, the drive sleeve30 may be machined directly into the gate 32. In other words, sleeve 30and gate 32 may be a one-piece structure. It should be appreciated thatwhen operating the valve 10, the drive sleeve/gate interface 43 may bedesigned to resist gate drag on the gate 32.

The upper end 52 of the drive sleeve 30 may include a sealing component54, such as an o-ring or other suitable seal. The sealing component 54isolates the interior of the drive sleeve 30 from the pressure in thevalve body 12, such as from valve lading in the valve chamber. The upperend of the drive sleeve 30 also includes external beveled edge 56 (alsoreferred to as an up-stop). As shown below in FIG. 3, the beveled edge56 of the drive sleeve 30 may abut the top 58 of the valve chamber tolimit travel of the gate 32 when the gate 32 is moved upward to an openposition. An upper portion 60 of the stem 18 may also be coated in a dryfilm lubricant or other suitable protective lubricant to prevent scale,particulates, or other materials from damaging the sealing component 54of the drive sleeve 30.

Grease or other lubricant may be disposed in an interior cavity 62defined by the drive sleeve 30 and the stem 18. To allow movement of thegrease during movement of the drive sleeve 30, the stem 18 may include apassage or chamber 64 that extends from the top of the stem 18 throughthe stem 18 toward the gate 32. As illustrated, the chamber 64 extendsto the interior cavity 62 (e.g., L-shaped passage). During operation ofthe valve 10 and movement of the drive sleeve 30, the grease may flowfrom the interior space 62 and into the chamber 64 of the stem 18 orvice-versa.

To open the valve 10, the handwheel 20 may be rotated in the directiongenerally indicated by arrow 65. Rotation of the handwheel 20 causes thestem 18 to rotate. As the stem 18 rotates, the threaded drivesleeve/stem interface 41 enables the drive sleeve 30 to move (e.g.,translate) along the stem 18 in the direction generally indicated byarrow 66. The drive sleeve/gate interface 43 thus causes the gate 32 toalso move (e.g., translate) in the direction indicated by arrow 66 untilthe port 34 of the gate 32 is aligned with the inlet and outlet passages22 and 24.

It should be appreciated that opening or closing the valve 10 may resultin overcoming the gate drag applied to the gate 32 by the valve ladingand the stem thrust applied to the stem 18 by the valve lading.Accordingly, the valve 10 may include thrust bearings (not shown)disposed outside the body cavity 40, such as in an upper portion 67 ofthe bonnet 16, to absorb the stem thrust pressure. Further, when openingor closing the valve 10, additional torque may be applied as a result ofpressure from the body cavity 40 applied to the sealing component. Thisadditional torque may be offset by the lubricant disposed in the cavity40.

FIG. 3 is a cross-section of the valve 10 in an open position inaccordance with an embodiment of the present invention. As shown in FIG.3, the port 34 is aligned with the inlet and outlet passages 22 and 24to allow valve lading to flow through the valve 10. The direction offlow is generally indicated by arrows 68. As the gate 32 moves in thedirection generally indicated by arrow 66, the stem 18 moves into arecess 70 of the gate 32. The gate 32 and drive sleeve 30 may be movedalong the stem 18 until the beveled edge 56 abuts the upper portion 60of the valve chamber 40. As the drive sleeve 30 moves in the directiongenerally indicated by arrow 66 and the interior space 62 decreases insize, grease disposed in the interior space 62 may flow into the chamber64 of the stem 18.

As seen in FIGS. 2 and 3, the interface 41 between the drive sleeve 30and the stem 18 is isolated from any valve lading in the inlet andoutlet passages 22 and 24 and the valve chamber 40. By isolating thisinterface 41, the threads 42 and 44 of the interface 41 are not exposedto abrading (or corrosion) by the valve lading, thus ensuring theintegrity of the threaded interface 41. Further, the gate 32 is notdirectly attached to the stem 18, eliminating any movement of thethreads 48 of the gate 32 during opening and closing of valve 10 andmovement of the gate 32, thus protecting this drive sleeve/gateinterface 43.

FIG. 4 is a close-up cross-sectional view of the drive sleeve 30, gate32 and stem 18 of the valve 10 in accordance with an embodiment of thepresent invention. As more clearly seen in the FIG. 4, the chamber 64has a lateral opening 72 open to the internal cavity 62 and extends fromthe internal cavity 62 into the stem 18. In some embodiments, thechamber 64 may by enclosed by the stem 18. In other embodiments, thechamber 64 may extend through the stem 18 and include a second opening73, such that the chamber 64 connects with the recess 70 of the gate 32so that grease or other lubricant may flow between the internal cavity62 and recess 70 during movement of the drive sleeve 30 and gate 32.

In one embodiment, the chamber 64 may be generally “L-shaped” such thatthe chamber 64 includes a 90 degree bend at a middle portion 74 of thestem 18. Thus, the opening 72 of the chamber 64 is open to the internalcavity 62 such that the opening 72 remains within the sealing component54, blocking valve lading from entering the chamber 64.

The drive sleeve 30 allows use of the non-rising stem gate valve 10 inapplications that would otherwise be precluded due to the presence ofabrasive valve lading. For example, the non-rising stem gate valve 10having the drive sleeve 30 may be used with abrasive drilling fluids andprovide the typical advantages of a non-rising stem gate valve, such asreduced input torque and smaller dimensional profile. As describedabove, the drive sleeve 30 substantially or completely eliminates anyexposure of the threaded stem interface 41 from the abrasive drillingfluids and isolates the moveable connection of the stem 18 from suchfluids.

Further, it should be appreciated that the drive sleeve 30 may be usedwith any type of gate valve to protect a stem from valve lading. Forexample, the drive sleeve 30 may be used in a rising stem gate valvesuch that the drive sleeve moves with the rising stem during actuationof the valve.

FIG. 5 is a block diagram that illustrates a mineral extraction system100 that may include the non-rising stem gate valve 10 in accordancewith embodiments of the present technique. The illustrated mineralextraction system 100 can be configured to extract various minerals andnatural resources, including hydrocarbons (e.g., oil and/or naturalgas), or configured to inject substances into the earth. In someembodiments, the mineral extraction system 100 is land-based (e.g., asurface system) or subsea (e.g., a subsea system). In the illustratedembodiment, the system 100 includes a wellhead 102 coupled to a mineraldeposit 104 via a well 106, wherein the well 106 includes a wellhead hub108 and a well-bore 110.

The wellhead hub 108 generally includes a large diameter hub that isdisposed at the termination of the well bore 110. The wellhead hub 108provides for the connection of the wellhead 102 to the well 106. In someembodiments, the wellhead 102 includes a connector that is coupled to acomplementary connector of the wellhead hub 108. For example, in oneembodiment, the wellhead hub 108 includes a DWHC (Deep Water HighCapacity) hub manufactured by Cameron, headquartered in Houston, Texas,and the wellhead 102 includes a complementary collet connector (e.g., aDWHC connector), also manufactured by Cameron.

The wellhead 102 typically includes multiple components that control andregulate activities and conditions associated with the well 106. In someembodiments, the wellhead 102 generally includes bodies, valves andseals that route produced minerals from the mineral deposit 104,provides for regulating pressure in the well 106, and provides for theinjection of chemicals into the well bore 110 (down-hole). For example,in the illustrated embodiment, the wellhead 102 includes what iscolloquially referred to as a christmas tree 112 (hereinafter, a tree),a tubing spool 114, and a hanger 116 (e.g., a tubing hanger or a casinghanger).

The system 100 may include other devices that are coupled to thewellhead 102, and devices that are used to assemble and control variouscomponents of the wellhead 102. For example, in the illustratedembodiment, the system 100 includes a tool 118 suspended from a drillstring 120. In certain embodiments, the tool 118 includes a running toolthat is lowered (e.g., run) from an offshore vessel to the well 106and/or the wellhead 102. In other embodiments, such as surface systems,the tool 118 may include a device suspended over and/or lowered into thewellhead 102 via a crane or other supporting device.

The tree 112 generally includes a variety of flow paths (e.g., bores),valves, fittings, and controls for operating the well 106. For instance,in some embodiments, the tree 112 includes a frame that is disposedabout a tree body, a flow-loop, actuators, and valves. Further, the tree112 generally provides fluid communication with the well 106. Forexample, in the illustrated embodiment, the tree 112 includes a treebore 122. The tree bore 122 provides for completion and workoverprocedures, such as the insertion of tools (e.g., the hanger 116) intothe well 106, the injection of various chemicals into the well 106(down-hole), and the like. Further, minerals extracted from the well 106(e.g., oil and natural gas) are generally regulated and routed via thetree 112. For instance, the tree 112 may be coupled to a jumper or aflowline that is tied back to other components, such as a manifold.Accordingly, in such an embodiment, produced minerals flow from the well106 to the manifold via the wellhead 102 and/or the tree 112 beforebeing routed to shipping or storage facilities.

The tubing spool 114 provides a base for the wellhead 24 and/or anintermediate connection between the wellhead hub 108 and the tree 112.Typically, the tubing spool 114 (also referred to as a tubing head) isone of many components in a modular subsea or surface mineral extractionsystem 100 that are run from an offshore vessel and/or a surfaceinstallation system. As illustrated, the tubing spool 114 includes atubing spool bore 124. The tubing spool bore 124 connects (e.g., enablesfluid communication between) the tree bore 122 and the well 106. Thus,the tubing spool bore 124 provides access to the well bore 110 forvarious completion procedures, worker procedures, and the like. Forexample, components can be run down to the wellhead 102 and disposed inthe tubing spool bore 124 to seal-off the well bore 110, to injectchemicals down-hole, to suspend tools down-hole, and/or to retrievetools from down-hole.

The illustrated hanger 116 (e.g., tubing hanger or casing hanger), forexample, is typically disposed within the wellhead 106 to secure tubingand casing suspended in the well bore 110, and to provide a path forhydraulic control fluid, chemical injections, and the like. The hanger116 includes a hanger bore 126 that extends through the center of thehanger 116, and that is in fluid communication with the tubing spoolbore 124 and the well bore 110. The mineral extraction system 100 mayinclude plugs and valves are employed to regulate the flow and pressuresof fluids in various bores and channels throughout the mineralextraction system 100. In some embodiments, these valves may include thenon-rising stem gate valve 10 having the drive sleeve 30. For example,the valve 10 may be included in the tree 112. The valve 10 may alsoregulate flow to and/or from the wellhead hub 108 and the mineraldeposit 104.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

1. A system, comprising: a valve, comprising: a valve body having achamber; a valve member disposed in the chamber of the valve body; avalve stem extending into the chamber; a rotational interface betweenthe valve stem and the valve member; and a sleeve disposed about therotational interface, wherein a sealing component and the sleeve sealthe rotational interface relative to the chamber.
 2. The system of claim1, wherein the valve stem is configured to rotate to cause movement ofthe valve member between an open position and a closed position.
 3. Thesystem of claim 1, wherein the rotational interface is configured toenable both rotation and axial movement.
 4. The system of claim 1,wherein the rotational interface comprises a threaded interface.
 5. Thesystem of claim 4, wherein the sealing component is disposed along anon-threaded interface.
 6. The system of claim 1, wherein the rotationalinterface is configured to enable axial movement between the valve stemand the valve member.
 7. The system of claim 1, wherein the rotationalinterface is configured to enable axial movement between the valve stemand the sleeve.
 8. The system of claim 1, wherein the valve member andthe sleeve are coupled together.
 9. The system of claim 1, wherein thevalve member and the sleeve are portions of a one-piece structure. 10.The system of claim 1, wherein the rotational interface is disposed in afirst portion of the sleeve, the sealing component is disposed in asecond portion of the sleeve, and an inner cavity is disposed in a thirdportion of the sleeve, wherein the inner cavity has a greater diameterthan the rotational interface.
 11. The system of claim 1, wherein thesleeve is disposed about the valve stem, wherein the rotationalinterface, an inner cavity, and the sealing component are disposedbetween the sleeve and the valve stem, wherein the inner cavity isdisposed axially between the rotational interface and the sealingcomponent.
 12. The system of claim 11, wherein the inner cavity isfluidly coupled to a passage extending into the valve stem.
 13. Thesystem of claim 12, wherein the passage extends through the valve stembetween the inner cavity and a recess in the valve member.
 14. Thesystem of claim 1, wherein the valve comprises a gate valve, and thevalve member comprises a gate.
 15. The system of claim 1, wherein thesleeve extends along at least half a length of the chamber in adirection along an axis of the valve stem.
 16. A system, comprising: avalve, comprising: a valve body having a chamber; a valve memberdisposed in the chamber of the valve body; a valve stem extending intothe chamber; a threaded interface between the valve stem and the valvemember; and a sleeve disposed about the threaded interface, wherein asealing component and the sleeve seal the threaded interface relative tothe chamber.
 17. The system of claim 16, wherein the valve stem isconfigured to rotate to cause movement of the valve member between anopen position and a closed position.
 18. The system of claim 16, whereinthe sealing component is disposed along a non-threaded interface. 19.The system of claim 16, wherein the threaded interface is disposed in afirst portion of the sleeve, the sealing component is disposed in asecond portion of the sleeve, and an inner cavity is disposed in a thirdportion of the sleeve axially between the threaded interface and thesealing component.
 20. The system of claim 19, wherein the inner cavityis fluidly coupled to a passage extending into the valve stem.
 21. Thesystem of claim 16, wherein the valve comprises a gate valve, and thevalve member comprises a gate.
 22. A system, comprising: a valve stemsleeve, comprising: a threaded interface within a first portion of thevalve stem sleeve; a sealing component within a second portion of thevalve stem sleeve; and an inner cavity within a third portion of thevalve stem sleeve axially between the threaded interface and the sealingcomponent, wherein the sealing component and the sleeve are configuredto seal the threaded interface relative to a chamber in a valve body ofa valve.
 23. The system of claim 22, wherein the inner cavity has agreater diameter than the threaded interface.
 24. The system of claim22, comprising a valve stem disposed in the valve stem sleeve, whereinthe valve stem is coupled to the valve stem sleeve along the threadedinterface, and the inner cavity is fluidly coupled to a passageextending into the valve stem.